Multi-electrode electron tube

ABSTRACT

A multi-electrode electron tube is disclosed in which between the cathode and the chamber anode there is provided a control grid composed of wires. The chambers of the chamber anode are formed by fins arranged perpendicularly to the anode surface facing toward the cathode, and a bottom which is a part of the anode surface facing the cathode and contained between the fins. At points of normal projections of each fin of the chamber anode on the control grid and/or the cathode there are disposed elements for directing the electron flow from the cathode to the bottom of the chambers of the chamber anode arranged so as to form a plurality of sections, each including a part of the emitting cathode surface, part of the control grid wires and the bottom of a corresponding chamber of the chamber anode positioned parallel to one another in the direction of the electron flow.

' United States Patent 191 Manyafov et al.

[ I MULTl-ELECTRODE ELECTRON TUBE 22 Filed: July 3,1972

21 Appl.No.: 268,888

52 us. c1. 313/299, 313/306 51 Int. Cl. H01j 1/46 58 Field of Search 313/265, 299, 300, 306 I [56] References Cited UNITED STATES PATENTS 2,254,095 8/1941 Thompson.. 313/299 x 3,107,313 10/1963 l-lechtel.... 313/299 X 2,607,020 8/1952 Lehmann 313/300 X FOREIGN PATENTS OR APPLICATIONS 643,779 6/1962 Canada 313/306 1111 3,790,000 1451 Feb. 5, 1974 Primary Examiner-John K. Corbin Attorney, Agent, or Firm--.lohn C. Holman et al.

[57] ABSTRACT A multi-electrode electron tube is disclosed in which between the cathode and the chamber anode there is provided a control grid composed of wires. The chambers of the chamber anode are formed by fins arranged perpendicularly to the anode surface facing toward the cathode, and a bottom which is a part of the anode surface facing the cathode and contained between the fins. At points of normal projections of each fin of the chamber anode on the control grid and/or the cathode there are disposed elements for directing the electron flow from the cathode to the bottom of the chambers of the chamber anode arranged so as to form a plurality of sections, each including a part of the emitting cathode surface, part of the control grid wires and the bottom of a corresponding chamber of the chamber, anode positioned parallel to one another in the direction of the electron flow.

6 Claims, 7 Drawing Figures MULTI-ELECTRODE ELECTRON TUBE BACKGROUND OF THE INVENTION The present invention relates to electron devices and, more particularly, to multi-electrode electron tubes.

Multi-electrode electron tubes are known in which a control grid composed of wires is disposed between the cathode and the chamber anode, and the chambers of the chamber anode are formed by fins arranged perpendicularly to the anode surface facing the cathode, and a bottom which is a part of the anode surface facing the cathode and positioned between the fins, the depth of the chambers being preferably larger than their width which is larger than the control grid wire spacing.

In these known electron tubes, the chambers of the chamber anode serve to reduce secondary emission from the anode to the adjacent grid. However, the effect of such an arrangement is not sufficient for suppressing secondary emission at the chamber anode, because the grid wires distort the electrical field and cause thereby the primary electrons to deflect from their path normal to the anode. As a result, the primary electrons bombard not only the bottom of the chambers but also their fins and release from the fins secondary electrons which are not absorbed by the anode chambers.

This circumstance worsens current distribution in the tube, makes it unfeasible to design tubes with a low residual anode voltage'and imposes restrictions on the increase of the efficiency and power output.

The above disadvantage is particularly pronounced in beam-type tetrodes when residual anode voltage V 9is lower than voltage U,, at the screen grid.

For these reasons, the above electron tubes fail to ensure large anode currents at low residual anode voltage and reduce dimensions of the tube.

At the same time, modern radio equipment and, particularly, distributed amplifiers require a high value of the parameter N I /U c which provides high efficiency of the tube at a high power output level (I,, m maximum anode current; U, residual anode voltage; c output capacitance).

SUMMARY OF THE INVENTION It is on object of the present invention to eliminate the above disadvantage.

It is an object of the present invention to provide a multi-electrode electron tube which makes it possible to draw high anode current at low anode voltage and ensure high anode circuit efficiency.

To accomplish the foregoing objects, in a multielectrode electron tube wherein a control grid composed of wires is disposed between the cathode and the chamber anode, while the chambers of the chamber anode are formed by fins arranged perpendicularly to the anode surface facing the cathode, and a bottom which is a part of the anode surface facing the cathode and contained between the fins, the depth ofthe chambers being preferably larger than their width which is larger than the control grid wire spacing, there are provided, according to this invention, elements for directing the flow of electrons from the cathode to the bottom of the anode chambers disposed at the points of a normal projection of each tin of the anode chambers on the control grid and/or the cathode and arranged so as to form a plurality of sections, each including a part of the emitting surface of the cathode, part of the control grid wires and the bottom of a corresponding chamber of the chamber anode disposed parallel to one another in the direction of the electron flow.

When the elements for directing the electron flow from the cathode to the bottom of the anode chambers are disposed on the control grid, it is advantageous if these elements are made in the form of metal collars.

When the elements for directing the electron flow from the cathode to the bottom of the anode chambers are disposed on the cathode, it is advantageous if these elements are made in the form of non-emitting surfaces.

When the elements for directing the electron flow from the cathode to the bottom of the anode chambers are disposed on the control grid and the cathode, it is advantageous if these elements are made in the form of metal collars and non-emitting surfaces, respectively.

This invention makes it possible to focus the primary electron flow on the bottom of the chambers due to the action of the above elements, to prevent primary electrons from striking the fins of the anode and, therefore, to appreciably improve current distribution in the electron tube, obtain very low residual anode voltages at high anode current values and to raise the efficiency of the anode circuit of the tube.

The lpresent invention is simple in embodiment and does not make the electron tube more complicated than the existing types.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood from the following description of specific embodiments thereof taken with reference to the accompanying drawings in which:

FIG. 1 is a partial side sectional view of an electron tube embodying the present invention;

FIG. 2 is an isometric view of the cathode, control and screen grids and the chamber anode of an electron tube embodying the present invention (with the electron flow shown) with a partial cut-out and crosssection of the chamber anode;

FIG. 3 is a side sectional view of the cathode, control and screen grids and the chamber anode of the second embodiment of the present invention with a partial cutout (a general view of the cathode is given);

FIG. 4 is an isometric view of the same elements with a partial cut-out;

FIG. 5 is a side sectional view of the cathode, control and screen grids and the chamber anode of the third embodiment of the present invention with a partial cutout (a general view of the cathode is given);

FIG. 6 is an-isometric view of the same elements with a partial cut-out;

FIG. 7 gives the anode and grid-anode characteristics of a known tetrode and a tetrode embodying the present invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT The multi-electrode electron tube embodying the present invention depicted in FIG. 1 comprises a cathode assembly I, a control grid 2, a screen grid 3, and a chamber anode 4 arranged coaxially with respect to one another at a predetermined distance.

The cathode assembly 1 includes a cylindrical cathode 5 coated with an emission layer forming an emitting surface 6 of the cathode 5, a heater 7 disposed inside the cathode 5, a cup 8 with an opening intended for fastening the heater 7 inside the cathode 5, and supports9 and 10 which hold the cathode assembly 1 to a mount 11 and connect it electrically to appropriate cathode terminals of pins 12 through a jumper (not shown in the drawing). The heater 7 has an electrical coupling with one of the pins 12 through a jumper 13.

The cylindrical control grid 2 is composed of wires 14 arranged along the generatrices of a cylinder and forming the active surface of the grid. The upper ends of the grid wires 14 are fixed in a cap 15 with a cylindrical hole, while the lower ends are fastened in a support 16 which joins the control grid 2 to a ring 17 soldered to a ceramic projection 18 of the mount 11 and connects it through a jumper (not shown) with an appropriate terminal of the grid 2 in one of the pins 12.

The cylindrical screen grid 3 is composed of wires 19 arranged along the generatrices of a cylinder and aligned with the wires 14 of the control grid 2. The wires 19 of the screen grid 3 are held together in a screen 20 with a centre opening for a ceramic assembly 21 which joins the upper terminal members of the cathode assembly 1, control grid 2 and the screen grid 3. The screen grid 3 is secured to the mount 11 by a support 22 and a metal ring 23 fastened to a seal 24.

On the cylindrical surface of the chamber anode 4 facing the cathode 5 are located chambers 25 formed by fins 26 arranged perpendicularly to the surface of the anode 4 facing the cathode 5 there.

A portion of the inside surface of the anode 4 between the adjacent fins 26 forms a bottom 27 of each chamber 25, each serving as an active surface of the chamber anode 4. The surface of the fins 26 facing inside the chamber 25 forms a side wall 28 of each chamber 25. The narrow part of each fin 26 facing the cathode 5 is an end face 29 of the fin 26.

The chambers 25 are of a depth preferably larger than their width which is larger than the spacing of the wires 14 of the control grid 2.

In the proposed embodiments of the present invention, the above values are as follows: the width of the chamber 25 is 3.5 mm; the depth of the chamber 25 is 7 mm; the diameterof the wires 14 of the control grid 2 if 0.15 mm; the spacing of the wires 14 of the control grid 2 is 0.9 mm.

The proposed invention allows the electron flow to be guided to each bottom 27 of each chamber 25 of the chamber anode 4 consequently primary electrons do not directly bombard the fins 26 of the chambers-25 and, since, the fins 26 are not heated, their thickness can be made sufficiently small. This feature renders it possible to provide chambers of sufficient width and high electron absorbing efficiency on a limited active surface of the anode, which is an advantage of electron tubes embodying the present invention as against known electron tubes. In the preferred embodiments of the invention the thickness of the fins 26 of the chamber anode 4 made from copper is equal to 0.5 mm.

Other embodiments of the invention may, however, have inserts of thickness other than the above.

The envelope of the proposed electron tube is formed by the outside surface of the chamber anode 4 having a vacuum-tight connection through a metal ring 30 with a ceramic cylinder 31 which, on its other side,

has vacuum-tight connection with the mount vl1 through seals 24 and 32, the seal 32 serving as the lead of the screen grid 3. An exhaust tube 33 is provided in the chamber anode 4 for evacuation of the electron tube; the outside surface of the chamber anode 4 carries heat-radiating wings 34 for anode cooling.

This construction of an electron tube is identical for all the three embodiments of the present invention.

Each proposed embodiment of the present invention comprises elements for directing the electron flow from the cathode 5 to the bottom 27 of the chambers 25 of the chamber anode 4 disposed at the points of normal projection of each fin 26 of the chambers 25 in the chamber anode 4 on the control grid 2 and/or the cathode 5 and arranged so as to form a plurality of sections, each including a part of the emitting surface 6 of the cathode 5, part of the wires 14 of the control grid 2 and the bottom 27 of the appropriate chamber 25 of the chamber anode 4 parallel-arranged in the direction of the electron flow.

In the first embodiment of the invention (FIGS. 1 and 2) the elements for directing the electron flow from the cathode 5 to the bottom 27 of the chambers 25 in the chamber anode 4 are positioned on the control grid 2 and made in the form of metal collars 35 arranged so as to form a plurality of sections (four sections in this embodiment), each including a part of the emitting surface 6 of the cathode 5, part of the wires 14 contained between the collars 35, and the bottom 27 of the chambers 25 of the chamber anode 4 parallel-arranged in the direction of the electron flow.

These elements made in the form of metal collars 35 must be connected electrically with the wires 14 of the control grid 2. It is advisable to secure the above metal collars 35 on the wires 14 of the control grid 2 rigidly, for instance, by resistance welding. In the present embodiment of the invention, the above elements are manufactured in the form of metal collars 35 from 0.15 mmdia. wire.

Other embodiments may use wire of larger diameters or parallel arrangement of two or more metal collars; the elements may be made in the form of strips or different shapes or as a part of the structure of the grid 2, for example, by electric spark treatment or stamping. The width of the above elements on the control grid 2 can be selected so that it equals l0100 percent of the thickness of the fin 26 of the chamber 25 in the chamber anode 4. A preferred width of the elements lies within 20-50 percent of the thickness of the fin 26.

In the second embodiment of the invention (FIGS. 3 and 4) the elements for directing the electron flow from the cathode 5 to the bottom 27 of the chambers 25 are provided on the cathode 5 and are non-emitting surfaces 36 in order to make the tube operative both at negative and positive voltages across the control grid 2.

The non-emitting surfaces 36 of the cathode 5 can be made in the form of metal strips attached to the emitting surface 6, or in the form of metal projections on the cathode 5 having grooves which hold the emission layer.

The strips of the non-emitting surfaces 36 are preferably 0-100 percent wider than the end face 29 of the fin 26.

In the third embodiment of the invention, the elements for directing the electron flow from the cathode 5 to the bottom 27 of the chambers 25 in the chamber anode 4 are provided both on the control grid 2 and on the cathode 5 which is illustrated in FIGS. 5 and 6.

Here, the elements positioned on the control grid.2 are metal collars 35 and the elements located on the cathode 5 are non-emitting surfaces 36.

The operating principle of an electron tube applicaheated by the heater 7, is subjected, on the one hand,

to the control action of the wires 14 of the control grid 2 and, on the other, to focussing by the above elements with the result that the electron flow is divided into parts 38 and directed to the bottom 27 of the chambers in the chamber anode 4.

If the metal collars (FIGS. 1 and 2) for directing the flow of electrons from the cathode 5 to the bottom 27 of the chambers 25 are disposed on the control grid 2 and if the voltage U at the control grid 2 does not exceed the inherent potential at the plane of the control grid 2 which, for example, in oscillator tubes with an oxide-coated cathode gives the following value: U, 09=(0.05 0.1 )U, a dual focusing effect is produced on the electron flow: first, by the wires 14 of the control grid 2 and, second, by the metal collars 35.

The spaces between the wires 14 of the control grid '2 which carry voltage below the quiescent potential,

act as collecting lenses. Electrons emitted by the cathode 5 are collected into narrow beams and pass between the wires 19 of the screen grid 3 to each chamber 25 of the chamber anode 4.

On the other hand, the metal collars 35 help set up an electric field of such a configuration that the electron flow is focussed and divided along the axis of the tube 'into'parts 38 due to which this primary electron flow does not impinge on the side walls 28 of the chambers 25 and the end faces 29 of the fins 26, and secondaryelectrons are released only from the bottom 27 of the chambers 25.

. If the depth of the chamber 25 is, for example, twice its width, secondary electrons liberated from the bottom 27 of the chambers 25 are effectively absorbed by the chamber 25 and secondary emission at the chamber anode 4 is considerably reduced.

In case the voltage U, at the control grid 2 exceeds the quiescent potential, dual focusing action is exerted 'on the electron flow. The defocussing action of the bers.

Thus, the first embodiment of the invention can be used to maximum advantage if the control grid 2 is negatively charged, or if the voltage at the positively charged control grid 2 is not above the quiescent potential.

Nevertheless, the invention can also be used in cases when the voltage at the control grid 2 exceeds the quiescent potential by a certain value which in each particular case depends on interelectrode distances, dimensions of the wires 14 and 19, of the grids 2 and 3, and of the metal collars 35, and also on voltages at the electrodes of the tube.

When operating the electron tube at voltages across the control grid 2 both below and above the quiescent potential, it is most advantageous to use the embodiment of the invention in which elements for directing the electron flow from the cathode 5 (FIGS. 3 and 4) to the bottom 27' of the chambers 25 are made in the form of the non-emitting surfaces 36 of the cathode 5.

In this case, electrons in an operating tube are emit- ,ted from parts of the emitting surface 6 of the heated cathode 5, while the non-emitting portions 36 do not produce electrons and, consequently, the electron flow 37 at the cathode 5 is divided into parts 38. Besides, th non-emitting surfaces 36 are made from material the work function of which is larger than the work function of the oxide coating. This sets up a contact potential difference between portions of the emitting surface 6 and the non-emitting parts 36 of the cathode 5 which has a focussing effect on the electron flow 37 in the vicinity of the cathode and, when properly used, helps divide more effectively the electron flow 37 into the parts 38. v

The second embodiment of the invention differs from the first one mainly in that the electron flow 37 is divided into parts 38 and focussed along the axis of the tube in the vicinity of the cathode where electron velocities are still low and, therefore, the effect of the above focussing is very high due to which primary electrons can impinge on the bottom 27 of the chambers 25 both at negative voltages at the control grid 2 andpositive voltages at the control grid 2 which are much higher than the premissible positive voltage for the first embodiment of the invention.

This condition permits an increase in the input voltage range for the control grid 2 and better power utilization.

In some cases it is advantageous to use an electron tube wherein the elements for directing the electron flow from the cathode 5 (FIGS. 5 and 6) to the bottom 27 of the chambers 25 are disposed both on the control grid 2 and the cathode 5.

A primary difference between this and foregoing embodiments of the invention is that the electron flow 37 divided into the parts 38 at the cathode 5 is dually focussed: first, along the tube axis in the vicinity of the cathode due to a contact potential difference between the non-emitting portions 36 and the portions of the emitting surface 6 of the cathode 5, and, second, in the space between the cathode 5 and the control grid 2 by the metal collars 35 positioned on the control grid 2.

This embodiment of the invention is suitable for use both at negative and positive voltages at the control grid 2. The extent of the voltage at the control grid 2 exceeding the quiescent potential for this embodiment also depends in each concrete case on the geometrical dimensions of the electrode system comprising elements for directing the flow of electrons from the cathode to the bottom of the chambers, and on the operating mode of the tube.

The present invention makes it possible to appreciably decrease the residual anode voltage. FIG. 7 illustrates the anode and grid-anode characteristics of a known tetrode and a tetrode embodying this invention,

n1. =f(U.,), where: 1,, anode current;

1, screen-grid current,

U, anode voltage.

Lines 39 and 40 are the characteristics of a known I rated. This separation allows in each concrete case to use control grid wires of a required thickness (both very small and sufficiently large) and, consequently, to ensure desired characteristics of the tube (power output; transconductance, gain, etc.), on the one hand, and to use sufficiently wide chambers 25 with thin fins 26 which are effective in absorbing secondary electrons, on the other.

These elements for directing the electron flow from the cathode to the bottom 27 of the chambers 25 in combination with these chambers formed by thin fins 26 and flat bottom 27, ensure high efficiency of suppressing secondary emission at the anode 4. At the same time, tubes of the above construction are very simple and easy to manufacture.

The present invention makes it possible to draw large anode currents at low residual anode voltages and to design a number of powerful electron tubes which warrant high efficiency of distributed amplifiers and improve the efficiency of resonant-type radio devices.

In the proposed electron tube designed as a tetrode where elements for directing the electron flow from the cathode 5 to the bottom 27 of the anode chambers 25 are provided on the control grid 2 only, residual voltage at the anode 4 is four imes as small as that in known tetrodes.

The efficiency of a distributed amplifier operating into a low-impedance load increases almost twice (from 30 percent to 55 percent).

In a distributed amplifier working into a highimpedance narrow-band load, the efficiency and power output are percent higher.

The use of the proposed electron tube in distributed amplifiers made it possible to reduce the number of required tubes by two times and the size of the equipment by 6-8 times as well as permitted a 50 percent reduction in the cost of the equipment.

The present invention can be used in electron tubes with flat electrodes.

While we have shown and described certain particular embodiments of the invention, it will be obvious to those skilled in the art that other changes and modifications may be made without departing from the invention in its broader aspects. We therefore intend in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What we claim is:

l. A multi-electrode electron-beam tube comprising: an envelope; a cathode located inside said envelope, said cathode having an emitting surface for emitting an electron flow; a chamber anode located insaid envelope with a surface facing the direction of said electron flow so as to receive electrons from said cathode during operation of the tube; a control grid located in said envelope between said cathode and said chamber anode and made in the form of spaced wires; fins of said chamber anode disposed at right angles to said surface of said chamber anode facing said cathode; chambers of said chamber anode defined by said fins the bottom of the chambers being a part of said surface of said chamber anode and situated between said fins, said chambers having their depth substantially greater than their width said width being larger than the spacing of said control grid wires; means for dividing said electron flow into parts and directing each of said parts to the bottom of a respective chamber of said chamber anode, said means being located at the points of a normal projection of each fin of said chamber anode on said wires of said control grid, said wires being located between said elements; a plurality of sections of said electron tube each containing a portion of said emitting surface of said cathode, a portion of said wires of said control grid and the bottom of a respective chamber of said chamber anode said sections being arranged in a mutually parallel relationship in the direction of said electron flow.

2. A multi-electrode electron-beam tube as claimed in claim 1, wherein said means for dividing said electron flow into parts and directing each of said parts of said electron flow from said cathode to the bottom of a respective chamber of said chamber anode are made in the form of metal collars disposed on said wires of said control grid.

3. A multi-electrode electron tube comprising: an envelope; a cathode located inside said envelope, said cathode having an emitting surface for emitting an electron flow; a chamber anode located in said envelope with a surface facing the direction of said electron flow so as to receive electrons from said cathode during operation of the tube; a control grid located in said envelope between said cathode and said chamber anode, and made in the form of spaced wires; fins of said chamber anode disposed at right angles to said surface of said chamber anode facing said cathode; chambers of said chamber anode defined by said fins the bottom of the chambers being a part of said surface of said chamber anode and situated between said fins, said chambers having their depth substantially greater than their width said width being greater than the spacing of said control grid wires; elements for dividing said electron flow into parts and directing each of said parts to the bottom of a respective chamber of said chamber anode, said elements being located at the points of normal projection of each fin of said chamber anode on said cathode, said wires being located opposite to areas of said emitting surface of said cathode; a plurality of sections of said electron tube each containing a part of said emitting surface of each cathode, a part of said wires of said control grid and the bottom of a respective chamber of said chamber anode said sections being arranged in a mutually parallel relationship in the direction of said electron flow.

4. A multi-electrode electron tube as claimed in claim 3, wherein said elements for driving said electron flow into parts and directing each of said parts of said electron flow from said cathode to the bottom of a respective chamber of said chamber anode are made in the form of emitting areas provided on said emitting surface of said cathode.

5. A multi-electrode electron tube comprising: an envelope; a cathode located inside said envelope, said cathode having an emitting surface for emitting an electron flow; a chamber anode located in said envelope with a surface facing the direction of said electron flow to receive electrons from said cathode during operation of the tube; a control grid located in said envelope between said cathode and said chamber anode, and made in the form of spaced wires; fins of said chamber anode disposed at right angles to said surface of said chamber anode facing said cathode; chambers of said chamber anode defined by said fins the bottom of the chambers forming a part of said surface of said chamber anode and situated between said fins, said chambers having their depth substantially greater than their width which is greater than the spacing of said control grid wires; elements for dividing said electron flow into parts and directing each of said parts to the bottom of a respective chamber of said chamber anode, said elements being located at the points of normal projection of each fin of said chamber anode on said wires of said control grid and on said cathode, said wires being located between said elements on said wires of said control grid and opposite to areas of said emitting surface of said cathode; a plurality of sections of said electron tube each containing a part of said emitting surface, a part of said wires of said control grid and the bottom of a respective chamber of said chamber anode said sections being arranged in a mutually parallel relationship in the direction of said electron flow.

6. A multi-electrode electron tube as claimed in claim 5, wherein said elements for dividing said electron flow into parts and directing each of said parts of said electron flow from said cathode to the bottom of a respective chamber of said chamber anode are provided on said control grid in the form of metal collars located on said wires of said control grid, and on said cathode, in the form of non-emitting areas provided on said emitting surface of said cathode. 

1. A multi-electrode electron-beam tube comprising: an envelope; a cathode located inside said envelope, said cathode having an emitting surface for emitting an electron flow; a chamber anode located in said envelope with a surface facing the direction of said electron flow so as to receive electrons from said cathode during operation of the tube; a control grid located in said envelope between said cathode and said chamber anode and made in the form of spaced wires; fins of said chamber anode disposed at right angles to said surface of said chamber anode facing said cathode; chambers of said chamber anode defined by said fins the bottom of the chambers being a part of said surface of said chamber anode and situated between said fins, said chambers having their depth substantially greater than their width said width being larger than the spacing of said control grid wires; means for dividing said electron flow into parts and directing each of said parts to the bottom of a respective chamber of said chamber anode, said means being located at the points of a normal projection of each fin of said chamber anode on said wires of said control grid, said wires being located between said elements; a plurality of sections of said electron tube each containing a portion of said emitting surface of said cathode, a portion of said wires of said control grid and the bottom of a respective chamber of said chamber anode said sections being arranged in a mutually parallel relationship in the direction of said electron flow.
 2. A multi-electrode electron-beam tube as claimed in claim 1, wherein said means for dividing said electron flow into parts and directing each of said parts of said electron flow from said cathode to the bottom of a respective chamber of said chamber anode are made in the form of metal collars disposed on said wires of said control grid.
 3. A multi-electrode electron tube comprising: an envelope; a cathode located inside said envelope, said cathode having an emitting surface for emitting an electron flow; a chamber anode located in said envelope with a surface facing the direction of said electron flow so as to receive electrons from said cathode during operation of the tube; a control grid located in said envelope between said cathode and said chamber anode, and made in the form of spaced wires; fins of said chamber anode disposed at right angles to said surface of said chamber anode facing said cathode; chambers of said chamber anode defined by said fins the bottom of the chambers being a part of said surface of said chamber anode and situated between said fins, said chambers having their depth substantially greater than their width said width being greater than the spacing of said control grid wires; elements for dividing said electron flow into parts and directing each of said parts to the bottom of a respective chamber of said chamber anode, said elements being located at the points of normal projection of each fin of said chamber anode on said cathode, said wires being located opposite to areas of said emitting surface of said cathode; a plurality of sections of said electron tube each containing a part of said emitting surface of each cathode, a part of said wires of said control grid and the bottom of a respective chamber of said chamber anode said sections being arranged in a mutually parallel relationship in the direction of said electron flow.
 4. A multi-electrode electron tube as claimed in claim 3, wherein said elements for driving said electron flow into parts and directing each of said parts of said electron flow from said cathode to the bottom of a respective chamber of said chamber anode are made in the form of emitting areas provided on said emitting surface of said cathode.
 5. A multi-electrode electron tube comprising: an envelope; a cathode located inside said envelope, said cathode having an emitting surface for emitting an electron flow; a chamber anode located in said envelope with a surface facing the direction of said electron flow to receive electrons from said cathode during operation of the tube; a control grid located in said envelope between said cathode and said chamber anode, and made in the form of spaced wires; fins of said chamber anode disposed at right angles to said surface of said chamber anode facing said cathode; chambers of said chamber anode defined by said fins the bottom of the chambers forming a part of said surface of said chamber anode and situated between said fins, said chambers having their depth substantially greater than their width which is greater than the spacing of said control grid wires; elements for dividing said electron flow into parts and directing each of said parts to the bottom of a respective chamber of said chamber anode, said elements being located at the points of normal projection of each fin of said chamber anode on said wires of said control grid and on said cathode, said wires being located between said elements on said wires of said control grid and opposite to areas of said emitting surface of said cathode; a plurality of sections of said electron tube each containing a part of said emitting surface, a part of said wires of said control grid and the bottom of a respective chamber of said chamber anode said sections being arranged in a mutually parallel relationship in the direction of said electron flow.
 6. A multi-electrode electron tube as claimed in claim 5, wherein said elements for dividing said electron flow into parts and directing each of said parts of said electron flow from said cathode to the bottom of a respective chamber of said chamber anode are provided on said control grid in the form of metal collars located on said wires of said control grid, and on said cathode, in the form of non-emitting areas provided on said emitting surface of said cathode. 